This is the page a payment opens on — but a payment carries its own link, and this one is bare. If you were sent here to pay something, open the link the merchant gave you; it ends in /checkout/… and holds the amount you agreed.
Setting a checkout up?
A buyer can never name their own price, so this page will not open without a session. The merchant's side makes one, and the buyer is sent to it. Two ways, depending on whether there is a site to check out from.
From your own site or app
Your server opens a session for the amount being charged, and sends the buyer to the address it answers with.
POST /v1/sessions
{ "amount_minor": 4200, "currency": "BRL" }
→ /checkout/<session>Without a site at all
Make a payment link in the merchant console and send it out of band — a message, an invoice, a chat. It opens this same page, and it can be given an expiry or revoked once it has done its job.
Card details are typed into the card vault's own fields and never pass through this page. Powered by tor.io.